ipHow to read an IPv4 address
Learn the four parts of an IPv4 address, valid number ranges, and the difference between an address and a port.
Read guideUnderstand your connection.
Practical guides to IP addresses, DNS, networking and privacy.
30 guidesIP addresses and port numbers: the difference
Learn how IP addresses identify destinations and ports identify services, including what a port number cannot prove.
Read guideWhat is IPv6? A practical guide to its addresses
Understand IPv6 notation, double-colon compression, and why a device can use more than one IPv6 address.
Read guideWhy is an IP lookup returning no result?
Troubleshoot lookup failures by distinguishing invalid input, private addresses, provider limits, and connection errors.
Read guideWhy does my IP location show another city?
Investigate an unexpected IP location through VPN exits, carrier routing, and outdated database records.
Read guideIs it safe to share your IP address?
Understand what an IP can reveal, how to share it in support requests, and its practical security limits.
Read guideHow to perform a bulk IP lookup
Prepare an IP list, compare bulk lookup results, and interpret failed entries without losing useful information.
Read guideWhat are localhost and 127.0.0.1?
Learn about loopback addresses, local development, and why localhost refers to a different machine for each user.
Read guideIPv4 vs IPv6: the differences that matter
Compare IPv4 and IPv6 addressing, dual-stack connections, and the reasons lookup results may differ.
Read guideWhy does your IP change on mobile internet?
Learn how mobile data, Wi-Fi, carrier exits, and shared addresses affect IP lookup results.
Read guide